國立虎尾科技大學 |

Endocytic Recycling Pathways in Aspergillus nidulans .

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Endocytic Recycling Pathways in Aspergillus nidulans ./
Author:	Schultzhaus, Zachary S.
Description:	1 online resource (192 pages)
Notes:	Source: Dissertation Abstracts International, Volume: 79-02(E), Section: B.
Contained By:	Dissertation Abstracts International79-02B(E).
Subject:	Microbiology. -
Online resource:	click for full text (PQDT)
ISBN:	9780355277890

Endocytic Recycling Pathways in Aspergillus nidulans .
Schultzhaus, Zachary S.

Endocytic Recycling Pathways in Aspergillus nidulans . - 1 online resource (192 pages)

Source: Dissertation Abstracts International, Volume: 79-02(E), Section: B.

Thesis (Ph.D.)--Texas A&M University, 2017.

Includes bibliographical references

Fungi, which dominate many ecosystems as major decomposers and pathogens, generally colonize through the formation of long, tubular cells called hyphae. Understanding hyphal growth has been of interest to cell biologists for a century, and holds the potential to provide insights for many eukaryotic systems. Hyphal growth and shape are intimately connected with membrane trafficking, which is divided into exocytosis (membrane fusion) and endocytosis (membrane fission). Both of these processes are, in turn, essential for hyphal growth. However, endocytosis works to remove membrane, and why it should be important for cell expansion is not known. Here, using genetic manipulation combined with live cell imaging, the role of endocytosis in hyphal growth was scrutinized in the fungus Aspergillus nidulans. First, I examined the localization and function of the canonical endocytic coat protein, clathrin, and discovered that it is involved in budding at the Golgi apparatus, but does not appear to play a significant role in endocytosis. Second, I looked for proteins that may traffic through an endocytic recycling pathway within the hyphal tip, which resulted in identification and characterization of the phospholipid flippases DnfA-D in A. nidulans. These proteins regulate phospholipid asymmetry in the plasma membrane and the endocytic pathway, and are predicted to be involved in linking endocytosis and exocytosis. I discovered that DnfA and DnfB are stratified within the hyphal tip, likely on different vesicles, and require endocytosis for their steady-state localization. Loss of either DnfA or DnfB function has a minor effect on hyphal shape and growth, but loss of both is lethal. Additionally, the phospholipid phosphatidylserine is normally concentrated strictly on the outside of secretory vesicles, but the localization of this phospholipid, as well as several secretory proteins, was disrupted and diffused through the cytoplasm in the absence of DnfA. These results highlight the importance of endocytic recycling in the maintenance of polarized hyphal growth, as well the complexity of the homeostatic mechanisms at work in an actively expanding hyphal cell, which involve proteins and a variety of lipids for normal function.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2018

Mode of access: World Wide Web

ISBN: 9780355277890Subjects--Topical Terms:

591510
Microbiology.
Index Terms--Genre/Form:

554714
Electronic books.

Endocytic Recycling Pathways in Aspergillus nidulans .
LDR:03506ntm a2200337Ki 4500 001 916365
005 20181002081324.5
006 m o u
007 cr mn||||a|a||
008 190606s2017 xx obm 000 0 eng d
020 $a 9780355277890
035 $a (MiAaPQ)AAI10662600
035 $a (MiAaPQ)0803vireo:18454Schultzhaus
035 $a AAI10662600
040 $a MiAaPQ $b eng $c MiAaPQ $d NTU
100 1 $a Schultzhaus, Zachary S. $3 1190069
245 1 0 $a Endocytic Recycling Pathways in Aspergillus nidulans .
264 0 $c 2017
300 $a 1 online resource (192 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
338 $a online resource $b cr $2 rdacarrier
500 $a Source: Dissertation Abstracts International, Volume: 79-02(E), Section: B.
500 $a Includes supplementary digital materials.
500 $a Adviser: Brian D. Shaw.
502 $a Thesis (Ph.D.)--Texas A&M University, 2017.
504 $a Includes bibliographical references
520 $a Fungi, which dominate many ecosystems as major decomposers and pathogens, generally colonize through the formation of long, tubular cells called hyphae. Understanding hyphal growth has been of interest to cell biologists for a century, and holds the potential to provide insights for many eukaryotic systems. Hyphal growth and shape are intimately connected with membrane trafficking, which is divided into exocytosis (membrane fusion) and endocytosis (membrane fission). Both of these processes are, in turn, essential for hyphal growth. However, endocytosis works to remove membrane, and why it should be important for cell expansion is not known. Here, using genetic manipulation combined with live cell imaging, the role of endocytosis in hyphal growth was scrutinized in the fungus Aspergillus nidulans. First, I examined the localization and function of the canonical endocytic coat protein, clathrin, and discovered that it is involved in budding at the Golgi apparatus, but does not appear to play a significant role in endocytosis. Second, I looked for proteins that may traffic through an endocytic recycling pathway within the hyphal tip, which resulted in identification and characterization of the phospholipid flippases DnfA-D in A. nidulans. These proteins regulate phospholipid asymmetry in the plasma membrane and the endocytic pathway, and are predicted to be involved in linking endocytosis and exocytosis. I discovered that DnfA and DnfB are stratified within the hyphal tip, likely on different vesicles, and require endocytosis for their steady-state localization. Loss of either DnfA or DnfB function has a minor effect on hyphal shape and growth, but loss of both is lethal. Additionally, the phospholipid phosphatidylserine is normally concentrated strictly on the outside of secretory vesicles, but the localization of this phospholipid, as well as several secretory proteins, was disrupted and diffused through the cytoplasm in the absence of DnfA. These results highlight the importance of endocytic recycling in the maintenance of polarized hyphal growth, as well the complexity of the homeostatic mechanisms at work in an actively expanding hyphal cell, which involve proteins and a variety of lipids for normal function.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2018
538 $a Mode of access: World Wide Web
650 4 $a Microbiology. $3 591510
655 7 $a Electronic books. $2 local $3 554714
690 $a 0410
710 2 $a ProQuest Information and Learning Co. $3 1178819
710 2 $a Texas A&M University. $b Plant Pathology and Microbiology. $3 1190070
773 0 $t Dissertation Abstracts International $g 79-02B(E).
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10662600 $z click for full text (PQDT)